In a communication system such as a mobile network, communication by users of the communication system passes through network functions (CPE (Customer Premises Equipment), BRAS (Broadband Remote Access Server), and the like) to obtain communication services performed by the network functions
PTL 1 (FIG. 1 and others) discloses a mobile network architecture. In PTL 1, a terminal such as a PC (Personal Computer) accesses the Internet via CPE and BRAS. A communication from the terminal obtains communication services for accessing the Internet through the CPE and BRAS.